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Green '02 E320 Wagon
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Discussion Starter #1
How can I remove and retorque the nut on the front upper control arm (to steering knuckle) when its bolt spins? The ball joint bolt has a hex cut out of its end to keep it from spinning, but the upper control arm bolt just has a smooth divet. Of course, I can't get to the other side of the control arm bolt because it's nested within the arm.

How can I remove and retorque that nut? My car is entirely apart and I have to put it back together tomorrow. Thanks.
 

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Outstanding Contributor , SDS Guru
1998 MB E300TD, 1997 MB E36 AMG, 2001 MB E55 AMG
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Can you post a picture? I'm having a hard time following which bolt you're referring to.
 

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'04 G55 '80 280GE '99 S420 '98 E320 2011 E350 2016 GLA250
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Do you mean the Ball joint 'bolt' is 'spinning' within the Socket?

Granted, this picture is from a W140, but I suspect it may be the similar situation....

Inhex bit in the Ball Joint 'Bolt' as a Counter-Stay, while you firmly tighten the Nut. If tight enough? The whole Joint/Bolt complex should not 'spin' as you use your Torque Wrench for final tightening. Remember, it should be tightened in a 'Road-Ready' state (ie. Weight-on-Wheels).

G
 

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Green '02 E320 Wagon
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Discussion Starter #4 (Edited)
I've attached a diagram of how I understand this to be working. When I turn the nut, the threaded shaft of the ball joint is spinning within the ball socket, and the hole in the steering knuckle is doing nothing to stop it. There is no hex embedded into the shaft end to use a counter stay, like the tie rod end and supporting joint have.

For the tie rod ends, I can overcome this by simulating the road-ready state: Put a jack stand under the tie rod end ball socket, then lower the car gently on to it. This jams the ball shaft up in to the steering knuckle hole, preventing the shaft from spinning while I loosen or torque the nut.

For the upper control arm, I see this as being the same problem, just upside down. So simulated road-ready state by putting a jack stand under the steering knuckle's ball joint socket and lowered the car. I also put a block of wood above the UCA to provide a stopping point for its upward swing. I thought this would jam the ball shaft into the steering knuckle hole, locking it in place. But when I turned the nut, the shaft spun right with it.

I tried the other wheel with the tire still on, fully on the ground. Turning the nut just spun the UCA bolt. I tried jamming the wood up in there again before lowering it but that also didn't work.

I tried cutting a slot into the end of the shaft to wedge metal in there to prevent it from spinning, but the metal just bent as the bolt spun. I tried a C clamp to compress the threads into the UCA ball joint, but that simply wore a hole in my C clamp. An impact wrench can't fit because the steering knuckle is curved. I tried heating the nut with a blow torch, not for too long to avoid melting the ball joint boot, but that did nothing. I've sprayed penetrating oil in there many times, so maybe that's just making the shaft spin worse and not helping the nut.

My last resort is to surgically cut off the nuts with a Dremel tool. And once I do this, how will I be able to torque the new nuts on when the job is done? It needs 45 Nm torque, which isn't much.

I really don't want to pay $1000 to get my wheel bearings replaced just because these two nuts are stuck. How would the dealership do it? Demand I get new UCA's? Two darn bolts have wasted over 10 hours of my time, turning a straightforward job into a nightmare.
 

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E320/E250 Bluetec Ford F350 6.7l
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For this application you want to use cone holding power.
If you broke the cone hold on removal, try to clean it with electronic cleaner and tap it with hammer to hold.
Then good impact wrench is crucial, while applying force to hold the cone would help.
I can't make it from the picture, but could you grab other end with vise-grips?
 

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Outstanding Contributor , SDS Guru
1998 MB E300TD, 1997 MB E36 AMG, 2001 MB E55 AMG
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Are you using hand tools for it?

For those ball joints that don't have a hex/torx recess to hold it.... Use an impact gun.

Worst comes to worst, use a grinder to cut out the nut, and replace the upper control arm.
 

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Green '02 E320 Wagon
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Discussion Starter #7
The impact wrench I have access to doesn't fit because the steering knuckle bends right into its way. I'll try one last time, then I'm cutting the nut with a Dremel. I better not mess up because I can't replace the UCAs. They're too hard, too expensive, and were just done seven years ago.
 

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Outstanding Contributor , SDS Guru
1998 MB E300TD, 1997 MB E36 AMG, 2001 MB E55 AMG
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No wobble sockets for the impact? They help a lot.
 

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Discussion Starter #9 (Edited)
I removed the upper control arm nut by surgically cutting it off with a Dremel tool. I then wire brushed the ball joint stud's threads and applied some oil to them. I was able to install a new nut and torque it properly without the stud spinning. So it was the rusty nut's fault all along.

I've heard that Fluid Film or CRC Corrosion Inhibitor are great for protecting bolts and nuts. I read that Fluid Film is lanolin based so it won't eat away at plastic and rubber like the petroleum based products like CRC. I will get some Fluid Film and spray it on my suspension bolts each year.
 

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E320/E250 Bluetec Ford F350 6.7l
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On the long run, think about climate change.
I spend enough of my life in "salt belt" where big chunk of my time was wasted only to fight elements and corrosion.
Not even talking about spending big chunk of the income on warm cloths and heating bills.
Not fun.
 
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